You probably already know this on some level, but the lighting you choose for your home is critical for the beauty and functionality of the space. Too often, people add the lighting as an afterthought, without much consideration for the overall effect or the need for useful illumination.
The first consideration should always be for function. If your project is for an entire house, consider each space within that house - whatever areas are considered whole unto themselves. Usually this is by rooms. Think first of how you see the room being used.

If this is a redesign it may be how it has been traditionally used, or you may take this opportunity to reshape it. Is it a room for work? For reading? For casual entertaining? For eating? For movie watching or music listening? A combination of these?
Next you should envision these activities more specifically. Where will they take place in the space? How much light will they require? A desk or table that will be worked at often will need dramatically different light than a painting to be highlighted on the wall. Also consider natural light - is the space bright enough during the day, or is there anywhere you would like it to be brighter?
There are 3 different kinds of lighting: background, task, and decorative. Each serves a specific and necessary purpose, and if layered properly, can show your room to its full advantage.

Background illumination is the first layer - it should compensate for natural light in the daytime and light the room evenly at night. This is most often done by ceiling fixtures, but it can also be achieved by lamps and sconces around the room, providing overlapping pools of light. Task lighting throws intense, focused light on a workspace for preparing food, working, reading, playing an instrument, etc. With the bright light comes contrasting shadows, so be sure to place the light source in front of or beside the person, never behind. Decorative lighting, also known as accent lighting, is bright light shown on something to accent it - all form and no function. It can be to emphasize a painting as mentioned before, or an architectural element, a beautiful piece of furniture, a sculpture, a collection of some sort. the list is as varied as people’s tastes.
You are now armed with the essential knowledge and questions you need to ask yourself to embark on the task of lighting your space. Done properly, it can be a showcase that is as functional as it is lovely.